Andrew's git - gitweb.git/blob

   1#include "builtin.h"
   2#include "cache.h"
   3#include "path-list.h"
   4#include "xdiff/xdiff.h"
   5#include "xdiff-interface.h"
   6
   7#include <time.h>
   8
   9static const char git_rerere_usage[] =
  10"git-rerere [clear | status | diff | gc]";
  11
  12/* these values are days */
  13static int cutoff_noresolve = 15;
  14static int cutoff_resolve = 60;
  15
  16/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
  17static int rerere_enabled = -1;
  18
  19static char *merge_rr_path;
  20
  21static const char *rr_path(const char *name, const char *file)
  22{
  23        return git_path("rr-cache/%s/%s", name, file);
  24}
  25
  26static void read_rr(struct path_list *rr)
  27{
  28        unsigned char sha1[20];
  29        char buf[PATH_MAX];
  30        FILE *in = fopen(merge_rr_path, "r");
  31        if (!in)
  32                return;
  33        while (fread(buf, 40, 1, in) == 1) {
  34                int i;
  35                char *name;
  36                if (get_sha1_hex(buf, sha1))
  37                        die("corrupt MERGE_RR");
  38                buf[40] = '\0';
  39                name = xstrdup(buf);
  40                if (fgetc(in) != '\t')
  41                        die("corrupt MERGE_RR");
  42                for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
  43                        ; /* do nothing */
  44                if (i == sizeof(buf))
  45                        die("filename too long");
  46                path_list_insert(buf, rr)->util = xstrdup(name);
  47        }
  48        fclose(in);
  49}
  50
  51static struct lock_file write_lock;
  52
  53static int write_rr(struct path_list *rr, int out_fd)
  54{
  55        int i;
  56        for (i = 0; i < rr->nr; i++) {
  57                const char *path = rr->items[i].path;
  58                int length = strlen(path) + 1;
  59                if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  60                    write_in_full(out_fd, "\t", 1) != 1 ||
  61                    write_in_full(out_fd, path, length) != length)
  62                        die("unable to write rerere record");
  63        }
  64        if (close(out_fd) != 0)
  65                die("unable to write rerere record");
  66        return commit_lock_file(&write_lock);
  67}
  68
  69struct buffer {
  70        char *ptr;
  71        int nr, alloc;
  72};
  73
  74static void append_line(struct buffer *buffer, const char *line)
  75{
  76        int len = strlen(line);
  77
  78        if (buffer->nr + len > buffer->alloc) {
  79                buffer->alloc = alloc_nr(buffer->nr + len);
  80                buffer->ptr = xrealloc(buffer->ptr, buffer->alloc);
  81        }
  82        memcpy(buffer->ptr + buffer->nr, line, len);
  83        buffer->nr += len;
  84}
  85
  86static void clear_buffer(struct buffer *buffer)
  87{
  88        free(buffer->ptr);
  89        buffer->ptr = NULL;
  90        buffer->nr = buffer->alloc = 0;
  91}
  92
  93static int handle_file(const char *path,
  94         unsigned char *sha1, const char *output)
  95{
  96        SHA_CTX ctx;
  97        char buf[1024];
  98        int hunk = 0, hunk_no = 0;
  99        struct buffer minus = { NULL, 0, 0 }, plus = { NULL, 0, 0 };
 100        struct buffer *one = &minus, *two = &plus;
 101        FILE *f = fopen(path, "r");
 102        FILE *out;
 103
 104        if (!f)
 105                return error("Could not open %s", path);
 106
 107        if (output) {
 108                out = fopen(output, "w");
 109                if (!out) {
 110                        fclose(f);
 111                        return error("Could not write %s", output);
 112                }
 113        } else
 114                out = NULL;
 115
 116        if (sha1)
 117                SHA1_Init(&ctx);
 118
 119        while (fgets(buf, sizeof(buf), f)) {
 120                if (!prefixcmp(buf, "<<<<<<< "))
 121                        hunk = 1;
 122                else if (!prefixcmp(buf, "======="))
 123                        hunk = 2;
 124                else if (!prefixcmp(buf, ">>>>>>> ")) {
 125                        int one_is_longer = (one->nr > two->nr);
 126                        int common_len = one_is_longer ? two->nr : one->nr;
 127                        int cmp = memcmp(one->ptr, two->ptr, common_len);
 128
 129                        hunk_no++;
 130                        hunk = 0;
 131                        if ((cmp > 0) || ((cmp == 0) && one_is_longer)) {
 132                                struct buffer *swap = one;
 133                                one = two;
 134                                two = swap;
 135                        }
 136                        if (out) {
 137                                fputs("<<<<<<<\n", out);
 138                                fwrite(one->ptr, one->nr, 1, out);
 139                                fputs("=======\n", out);
 140                                fwrite(two->ptr, two->nr, 1, out);
 141                                fputs(">>>>>>>\n", out);
 142                        }
 143                        if (sha1) {
 144                                SHA1_Update(&ctx, one->ptr, one->nr);
 145                                SHA1_Update(&ctx, "\0", 1);
 146                                SHA1_Update(&ctx, two->ptr, two->nr);
 147                                SHA1_Update(&ctx, "\0", 1);
 148                        }
 149                        clear_buffer(one);
 150                        clear_buffer(two);
 151                } else if (hunk == 1)
 152                        append_line(one, buf);
 153                else if (hunk == 2)
 154                        append_line(two, buf);
 155                else if (out)
 156                        fputs(buf, out);
 157        }
 158
 159        fclose(f);
 160        if (out)
 161                fclose(out);
 162        if (sha1)
 163                SHA1_Final(sha1, &ctx);
 164        return hunk_no;
 165}
 166
 167static int find_conflict(struct path_list *conflict)
 168{
 169        int i;
 170        if (read_cache() < 0)
 171                return error("Could not read index");
 172        for (i = 0; i+1 < active_nr; i++) {
 173                struct cache_entry *e2 = active_cache[i];
 174                struct cache_entry *e3 = active_cache[i+1];
 175                if (ce_stage(e2) == 2 &&
 176                    ce_stage(e3) == 3 &&
 177                    ce_same_name(e2, e3) &&
 178                    S_ISREG(ntohl(e2->ce_mode)) &&
 179                    S_ISREG(ntohl(e3->ce_mode))) {
 180                        path_list_insert((const char *)e2->name, conflict);
 181                        i++; /* skip over both #2 and #3 */
 182                }
 183        }
 184        return 0;
 185}
 186
 187static int merge(const char *name, const char *path)
 188{
 189        int ret;
 190        mmfile_t cur, base, other;
 191        mmbuffer_t result = {NULL, 0};
 192        xpparam_t xpp = {XDF_NEED_MINIMAL};
 193
 194        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 195                return 1;
 196
 197        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 198                        read_mmfile(&base, rr_path(name, "preimage")) ||
 199                        read_mmfile(&other, rr_path(name, "postimage")))
 200                return 1;
 201        ret = xdl_merge(&base, &cur, "", &other, "",
 202                        &xpp, XDL_MERGE_ZEALOUS, &result);
 203        if (!ret) {
 204                FILE *f = fopen(path, "w");
 205                if (!f)
 206                        return error("Could not write to %s", path);
 207                fwrite(result.ptr, result.size, 1, f);
 208                fclose(f);
 209        }
 210
 211        free(cur.ptr);
 212        free(base.ptr);
 213        free(other.ptr);
 214        free(result.ptr);
 215
 216        return ret;
 217}
 218
 219static void unlink_rr_item(const char *name)
 220{
 221        unlink(rr_path(name, "thisimage"));
 222        unlink(rr_path(name, "preimage"));
 223        unlink(rr_path(name, "postimage"));
 224        rmdir(git_path("rr-cache/%s", name));
 225}
 226
 227static void garbage_collect(struct path_list *rr)
 228{
 229        struct path_list to_remove = { NULL, 0, 0, 1 };
 230        char buf[1024];
 231        DIR *dir;
 232        struct dirent *e;
 233        int len, i, cutoff;
 234        time_t now = time(NULL), then;
 235
 236        strlcpy(buf, git_path("rr-cache"), sizeof(buf));
 237        len = strlen(buf);
 238        dir = opendir(buf);
 239        strcpy(buf + len++, "/");
 240        while ((e = readdir(dir))) {
 241                const char *name = e->d_name;
 242                struct stat st;
 243                if (name[0] == '.' && (name[1] == '\0' ||
 244                                        (name[1] == '.' && name[2] == '\0')))
 245                        continue;
 246                i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
 247                strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
 248                if (stat(buf, &st))
 249                        continue;
 250                then = st.st_mtime;
 251                strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
 252                cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
 253                if (then < now - cutoff * 86400) {
 254                        buf[len + i] = '\0';
 255                        path_list_insert(xstrdup(name), &to_remove);
 256                }
 257        }
 258        for (i = 0; i < to_remove.nr; i++)
 259                unlink_rr_item(to_remove.items[i].path);
 260        path_list_clear(&to_remove, 0);
 261}
 262
 263static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 264{
 265        int i;
 266        for (i = 0; i < nbuf; i++)
 267                if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
 268                        return -1;
 269        return 0;
 270}
 271
 272static int diff_two(const char *file1, const char *label1,
 273                const char *file2, const char *label2)
 274{
 275        xpparam_t xpp;
 276        xdemitconf_t xecfg;
 277        xdemitcb_t ecb;
 278        mmfile_t minus, plus;
 279
 280        if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
 281                return 1;
 282
 283        printf("--- a/%s\n+++ b/%s\n", label1, label2);
 284        fflush(stdout);
 285        xpp.flags = XDF_NEED_MINIMAL;
 286        memset(&xecfg, 0, sizeof(xecfg));
 287        xecfg.ctxlen = 3;
 288        ecb.outf = outf;
 289        xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 290
 291        free(minus.ptr);
 292        free(plus.ptr);
 293        return 0;
 294}
 295
 296static int copy_file(const char *src, const char *dest)
 297{
 298        FILE *in, *out;
 299        char buffer[32768];
 300        int count;
 301
 302        if (!(in = fopen(src, "r")))
 303                return error("Could not open %s", src);
 304        if (!(out = fopen(dest, "w")))
 305                return error("Could not open %s", dest);
 306        while ((count = fread(buffer, 1, sizeof(buffer), in)))
 307                fwrite(buffer, 1, count, out);
 308        fclose(in);
 309        fclose(out);
 310        return 0;
 311}
 312
 313static int do_plain_rerere(struct path_list *rr, int fd)
 314{
 315        struct path_list conflict = { NULL, 0, 0, 1 };
 316        int i;
 317
 318        find_conflict(&conflict);
 319
 320        /*
 321         * MERGE_RR records paths with conflicts immediately after merge
 322         * failed.  Some of the conflicted paths might have been hand resolved
 323         * in the working tree since then, but the initial run would catch all
 324         * and register their preimages.
 325         */
 326
 327        for (i = 0; i < conflict.nr; i++) {
 328                const char *path = conflict.items[i].path;
 329                if (!path_list_has_path(rr, path)) {
 330                        unsigned char sha1[20];
 331                        char *hex;
 332                        int ret;
 333                        ret = handle_file(path, sha1, NULL);
 334                        if (ret < 1)
 335                                continue;
 336                        hex = xstrdup(sha1_to_hex(sha1));
 337                        path_list_insert(path, rr)->util = hex;
 338                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 339                                continue;;
 340                        handle_file(path, NULL, rr_path(hex, "preimage"));
 341                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 342                }
 343        }
 344
 345        /*
 346         * Now some of the paths that had conflicts earlier might have been
 347         * hand resolved.  Others may be similar to a conflict already that
 348         * was resolved before.
 349         */
 350
 351        for (i = 0; i < rr->nr; i++) {
 352                struct stat st;
 353                int ret;
 354                const char *path = rr->items[i].path;
 355                const char *name = (const char *)rr->items[i].util;
 356
 357                if (!stat(rr_path(name, "preimage"), &st) &&
 358                                !stat(rr_path(name, "postimage"), &st)) {
 359                        if (!merge(name, path)) {
 360                                fprintf(stderr, "Resolved '%s' using "
 361                                                "previous resolution.\n", path);
 362                                goto tail_optimization;
 363                        }
 364                }
 365
 366                /* Let's see if we have resolved it. */
 367                ret = handle_file(path, NULL, NULL);
 368                if (ret)
 369                        continue;
 370
 371                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 372                copy_file(path, rr_path(name, "postimage"));
 373tail_optimization:
 374                if (i < rr->nr - 1)
 375                        memmove(rr->items + i,
 376                                rr->items + i + 1,
 377                                sizeof(rr->items[0]) * (rr->nr - i - 1));
 378                rr->nr--;
 379                i--;
 380        }
 381
 382        return write_rr(rr, fd);
 383}
 384
 385static int git_rerere_config(const char *var, const char *value)
 386{
 387        if (!strcmp(var, "gc.rerereresolved"))
 388                cutoff_resolve = git_config_int(var, value);
 389        else if (!strcmp(var, "gc.rerereunresolved"))
 390                cutoff_noresolve = git_config_int(var, value);
 391        else if (!strcmp(var, "rerere.enabled"))
 392                rerere_enabled = git_config_bool(var, value);
 393        else
 394                return git_default_config(var, value);
 395        return 0;
 396}
 397
 398static int is_rerere_enabled(void)
 399{
 400        struct stat st;
 401        const char *rr_cache;
 402        int rr_cache_exists;
 403
 404        if (!rerere_enabled)
 405                return 0;
 406
 407        rr_cache = git_path("rr-cache");
 408        rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
 409        if (rerere_enabled < 0)
 410                return rr_cache_exists;
 411
 412        if (!rr_cache_exists &&
 413            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 414                die("Could not create directory %s", rr_cache);
 415        return 1;
 416}
 417
 418int cmd_rerere(int argc, const char **argv, const char *prefix)
 419{
 420        struct path_list merge_rr = { NULL, 0, 0, 1 };
 421        int i, fd = -1;
 422
 423        git_config(git_rerere_config);
 424        if (!is_rerere_enabled())
 425                return 0;
 426
 427        merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
 428        fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 429        read_rr(&merge_rr);
 430
 431        if (argc < 2)
 432                return do_plain_rerere(&merge_rr, fd);
 433        else if (!strcmp(argv[1], "clear")) {
 434                for (i = 0; i < merge_rr.nr; i++) {
 435                        struct stat st;
 436                        const char *name = (const char *)merge_rr.items[i].util;
 437                        if (!stat(git_path("rr-cache/%s", name), &st) &&
 438                                        S_ISDIR(st.st_mode) &&
 439                                        stat(rr_path(name, "postimage"), &st))
 440                                unlink_rr_item(name);
 441                }
 442                unlink(merge_rr_path);
 443        } else if (!strcmp(argv[1], "gc"))
 444                garbage_collect(&merge_rr);
 445        else if (!strcmp(argv[1], "status"))
 446                for (i = 0; i < merge_rr.nr; i++)
 447                        printf("%s\n", merge_rr.items[i].path);
 448        else if (!strcmp(argv[1], "diff"))
 449                for (i = 0; i < merge_rr.nr; i++) {
 450                        const char *path = merge_rr.items[i].path;
 451                        const char *name = (const char *)merge_rr.items[i].util;
 452                        diff_two(rr_path(name, "preimage"), path, path, path);
 453                }
 454        else
 455                usage(git_rerere_usage);
 456
 457        path_list_clear(&merge_rr, 1);
 458        return 0;
 459}